How do you prioritize your time?

So I'm running a successful, profitable solo business online which is in a niche that a lot of other shiny new startups don't yet want to touch. It's not a super sexy business, but it definitely generates money. I think I'm just about the best at running this business because nobody else is even remotely close in terms of quality, and it does make a noticeable difference in customer satisfaction. It's a very very successful business.<br><br>The problem is, it takes a lot of my time to do it this way. I work about 12 hours a day, 7 days a week. If I worked fewer hours and was less efficient with my time, I'd make less money, but I don't think my income would ever actually drop to anywhere near normal salary levels. So let's say I work 4 hours a day and cut my income in half.<br><br>But then I have a lot of free time. Even if I spend half my day working, there's potentially 12 hours in a day left, in which I can do anything I want. So let's say I work 4 hours a day, and then I spend 4 hours a day on my other passions. Let's say I think I'd be a great songwriter, and it brings me a lot of fulfillment. I spend 4 hours a day on songwriting. It's never going to amount to much, but again, I can be the best at it because I'm putting in so many hours, so I'm at least really good at songwriting even if I don't have a lot of audience. It's very fulfilling.<br><br>Then I have 4 hours a day left. Maybe I want to spend that improving my business, 50% more efficient with my time might double my income to more than double what I had before, while also allowing me to work fewer hours than now. Which is what I've actually done, constantly.<br><br>I've also found lately that I'm just running out of steam. I was very happy working long days in my 20s, but now in my 30s I don't have the endurance I used to. I'm in great shape but I can just feel that my mind isn't as sharp or as energetic. Sometimes I just want to take the day off.<br><br>So let's say it's a Sunday. I don't work Sundays because I need at least one day of rest. I have the morning free, I can do anything I want in the morning. My first instinct is always "I should work, because I've been lazy lately and my business needs this time." But the other side of me is "I should do something I love. I should work on my songwriting because I'm never going to be a great songwriter if I don't work on it, and it brings me so much joy. I want to be a great songwriter."<br><br>So I just want to hear your thoughts on this. Is there ever a time when it's okay to choose self fulfillment and joy over doing something for your business and income? I can't decide whether work is more important or my joy is more important.